It’s one of the most famous taglines in film history, even more recognizable than “Play it again, Sam” or “Houston, we have a problem” – and it’s only one of many that appeared on “Alien” posters in 1979.

“Once again something has come from space and this time, it’s not a friend,” one said. “Prepare yourself,” warned another.

In a post-“Jaws” and “Star Wars” world, the demand for big-budget thriller and science-fiction movies was high. Ridley Scott, who won the Best Debut Film award in 1977 for his historical drama “The Duellists,” accepted an offer to direct a film about a team of astronauts picked off one by one by a hostile space organism. Thus, the birth of “Alien” – which Scott has revisited 33 years later in the form of a prequel, “Prometheus.”

The enormous hype surrounding the $120-130 million “Prometheus,” which revisits the mysterious “space jockey” in “Alien,” suggests the cultural power of the latter. Not only did the Nostromo crew’s battle against the alien astound and alarm audiences in 1979, it established a new genre of female action hero and it has remained a topic of conversation in Hollywood boardrooms and around kitchen tables.

“‘Alien’ was an acid-burned anecdote to the dewy-eyed optimism of ‘Close Encounters’ and ‘Star Wars,’" one documentary feature says. “This was future fantasy with razor-sharp fangs, a groundbreaking genre classic which gave nightmarish fall to unspeakable anxieties.”

Intent on making “Alien” better than a B-rated movie, co-writers Dan O’Bannon and Ron Shusett were unsure what the hostile organism should look like, or how it would get aboard Nostromo. All they knew is that it needed to be “horrific and visceral.” One night, Shusett woke up with the inspiration he needed – the facehugger, which plants an alien embryo inside Executive Officer Kane (John Hurt).

Upon realizing Kane has been contaminated, warrant officer Ellen Ripley (Sigourney Weaver) refuses to let him aboard Nostromo. This proves to be the first of many instances in which Ripley displays better judgment than her superiors. She is the only survivor at the end of “Alien” and has since become the face of the franchise, rated No. 1 on Total Film’s list of the 100 Greatest Female Characters.

Eventually, the alien inside Kane bursts from his chest and begins its murderous rampage. Unlike films of the time like “Star Wars” – although similar to “Jaws” – the man-versus-monster battle takes place in a confined area with no way out. And as the great white shark did for “Jaws,” fear of the unknown (and of silence) catapulted “Alien” to big box office numbers and critical acclaim.

“One of the great strengths of ‘Alien’ is its pacing,” film critic Roger Ebert said in a review of the director’s cut of the film, which was released in 2003. “It takes its time. It waits. It allows silences…a recent version of this story would have hurtled toward the part where the alien jumps on the crew members.”

Scott’s directing style influenced subsequent horror films such as “Halloween,” which relied on slow and pacing and eerie soundtracks to create an anticipatory effect in viewers. Aside from the end of “Alien,” when Ripley blows the monster out of the shuttle into space, the tall, metallic-looking creature makes only minor appearances. The rest of the film follows the Nostromo crew as they navigate around the ship’s dark corners, often in silence or accompanied by the violin creaks of Jerry Goldsmith’s score, building up the fear of the unknown.

Likewise, O’Bannon and his team’s cynicism regarding space exploration (specifically, the idea that corporations in space would be as corrupt as they are on Earth) further helped legitimized the science fiction and horror genres in their exploration of political and societal problems. In the film, the android and science officer Ash tries to prevent Ripley and the crew from killing the alien based on orders from the corporation that owns Nostromo, a plot point that continues in “Aliens” (1986).

Even years after the release of “Alien,” some cast members have spoken out about the continued historical and symbolic importance of the film, as have those involved with “Prometheus.”